Smartphone-based device could detect SARS-CoV-2.

Researchers are developing a portable device that gives rapid, accurate test results with the help of a regular smartphone camera. By estimating the number of virus particles in samples, the device could also determine an infection's progress. A recent survey in the United States revealed that it takes an average of 4 days to receive a definitive SARS-CoV-2 lab test result after a nasal swab. Lab-based tests are much more reliable than rapid, on-the-spot tests for SARS-CoV-2, the virus that causes COVID19. They use a technique calledpolymerase chain reaction (PCR) to 'amplify' the minuscule amounts of viral genetic material in a sample.

But the tests are timeconsuming, increasing the risk of viral transmission while people wait for...